<div>I just did a little research on what I'd remembered about the differences, and came up with some interesting tidbits.</div>

<div>From the electronics industry's perspective, there are two shortcomings of leadfree solders. First, the higher tin content can lead to "tin whiskers," a phenomenon where the solder's surface grows a forest of microscopic branches -- some of which can grow long enough to bridge the distance between adjacent solder joints, and short the connections together. This seems to be a problem mostly with very fine surface mount devices.</div>

<div>The second problem is that soldering iron tips wear out much more quickly. The tin, again, at the higher melting temperature attacks the iron coating of the tip. The solution here is mostly to keep the iron at a temperature that's not _too_ high; the iron manufacturer Weller recommends 725F. Keep the tip well coated and replace when worn.</div>

<div dir="ltr">I believe lead based solder is generally easier to work with as it has a lower melting temperature. The downside is that it obviously contains lead. The lead-free stuff requires higher temperatures and can be slightly trickier to use but I haven't ever found it to be a problem.</div>

<div class="MsoNormal"><span style="font-size:10.0pt;font-family:">On another note, I just got a spool of lead-free solder which I will bring in the next time we come - please help yourself to it (I don't know much about this and wasn't sure if there is some advantage to the lead?) </span><u></u><u></u></div>